Attaching filaments to leading-in wires.



W. R. WHITNEY. ATTAGHING PILAMENTS T0 LEADING-IN WIRES. APPLICATION mum Jmmn, 1907.

1,01 3,914, Patented Jan. 9,1912.

Witnesses:

Inventor; Willis R. hi'bne g,

' ily to manipulation and cannot be bent andaoraara WILLIS R. WHITNEY, OF SCHENEGTAJDY, NEW YORK, ASSIGNORTO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

Application filed June 14, 1907. Serial No. 378,933.

Specification of Letters Patent.

Patented Jan. 9, WM.

To all whom it may concern:

Be it known that I, WILLIS R. WHITNEY, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Attaching Filaments to Leading-in Wires, of which the following .is -a ..specification.

According to my present invention metal lamp filaments may be connected with their leadlng-in conductors by purely mechanical means and without the use of any foreign material which might possibly contaminate the filament or the lam vacuum, or otherwise impair the material of the filament. The novel connections hereinafter described are produced by a new process, and although the process is applicable to lamp filaments of either tungsten or molybdenum, I have hereinafter described the process as applied to tungsten. I desire, however, that this specification shall be construed as applying also to molybdenum and that, in this relation, the two materials may be regarded as equivalents.

Tun ten are brittle and quite devoid of ductility and they therefore do not lend themselves readtwisted like filaments of more ductile material. I find, however, that when the tungsten is treated as hereinafter described, it is put in such physical condition that it can be bent and otherwise manipulated and can, while in this state, be distorted to produce a good mechanical connection with the leading-in conductor.

The accompanying drawing illustrates, in

Figure 1, a lamp embodying my invention.-

Fig. 2 is an illustration of the connection between filament and leading-in conductors, much. magnified; Figs. 3 and, 4 are enlarged views of a modified connection before and after the joint is completed.

Tungsten filaments can be produced in various ways, including, among others, the

-' processes described in British Patents Nos.

I I may use the arrangement illustrated.

To mount these coherent filaments of pure tungsten in a lamp I may use the arrangefilaments as ordinarily produced ment illustrated in Fig. 1, in which 1 is a.

central pedestal of glass or other non-conducting material carrying a plurality of copper or nickel wires 2 bent to form radial arms and having sockets at their outer ends for engagement with twisted wire loops 3 of tantalum. The filaments ma be en ported by these tantalum loops an may E metrically disposedabout the central pedestal 1. The leading-in conductors 4 at the base of the lamp may be of nickel or plati-' num and each provided at its end with a loop, spiral or similar device forming a socket for the lower end of the, filament.

The socket may be of the simple form shown in Fig. 2, in which the leading-in conductor 4 is merely flattened out into a book 5 engaging with the leg 6 of the tungsten filament, or it may be of the more com lex form shown in Fig. 3 in which the leadingin conductor is shaped into a'helix" 7.

To complete the joint between the filament e symand the leading-in conductor, I squeeze the very hot, and in fact, should preferably be at about visible redness. At such low temperatures the tungsten filament does not oxidize and is not injured by the operation. Even if the pliers be hotter and the tungsten be oxidized superficially the product is still serviceable. As soon as the joint cools, the tungsten resumes its non-ductile and brittle character. It retains permanently its distorted shape and the joint is entirely free from vaporizable material.

What I claim as new anddesire to secure by Letters Patent of the United States, is,

1. The method of attaching a tungsten lamp filament to a leading-in conductor which consists in pressing one about the other while the filament is heated to a temperature lower than that at which tungsten oxidizes in air.

2; The method of attaching a non-ductile lamp filament to a leading-in conductor which consists in rendering a portion of said filament pliant by heating and thenpressing In witness whereof, -I have hereilhto set the filament into intimate contact with the my hand this 12th day of June,'1907. v leading-in conductor and locking it vthereto.

3. A joint between a, fragile metal filai WILLIS 'Y I 5 ment and its supply conductorcomprising j Witnesses: f

a spiral on said conductor pinched tight t, BENJAMIN B. HUL

about said.filament and. holding it in place. HELEN 'ORFoRD. 

